Hint:
Ax+By+C= D
is parallel to
Ax+By+C= E
So in this case,
2x−9y+4z=5
is parallel to
2x−9y+4z=k
for any real number k
A 3x3 matrix has a characteristic polynomial of degree 3. If all the elements of the matrix are real, then the polynomial has up to 3 distinct complex roots. If one of these roots is complex (in particular, has a non-zero imaginary part), then a second root would be that first root's complex conjugate. Then the remaining root has to be real.
The answer is B. Substitute the x and the y in the ordered pair in for x and y in the equations.